All elements are made up of atoms. ➢ Atoms are made up of protons, neutrons, and electrons. Two different kinds of atoms can combine to form a compound. A molecule is a combination of atoms that cannot be broken apart while still retaining the same properties as the larger substance that it is a part of.
Answer:
single replacement
Explanation:
Step 1: Data given
single replacement = A reaction in which one element replaces a similar element in a compound. For example, a metal replaces an other metal.
The general form of a single-replacement (also called single-displacement) reaction is:
A+BC→AC+B
Decomposition = a reaction in which a compound breaks down into two or more simpler substances. The general form of a decomposition reaction is:
AB→A+B
Synthesis = A reaction that occurs when one or more compounds combines to form a complex compound:
A + B → AB
Double replacement: a reaction in which the positive and negative ions of two ionic compounds exchange places to form two new compounds.
The general form of a double-replacement reaction is:
AB+CD→AD+BC
Combustion reaction = a reaction in which a substance reacts with oxygen gas, releasing energy in the form of light and heat. Combustion reactions must involve O2 as one reactant.
The reaction Zn + 2HCl → ZnCl2 + H2
⇒ Does not involve O2 = NOT a combustion reaction
⇒ The compounds do not form a complex compound = NOT a synthesis
⇒ A compound does not break down into smaller substances = NOT a decomposition
⇒ There is a replacement between Zn and H. This is a <u>single replacement</u>, not a double replacement reaction.
Answer:
The amount of energy released from the combustion of 2 moles of methae is 1,605.08 kJ/mol
Explanation:
The chemical reaction of the combustion of methane is given as follows;
CH₄ (g) + 2O₂ (g) → CO₂ (g) + 2H₂O (g)
Hence, 1 mole of methane combines with 2 moles of oxygen gas to form 1 mole of carbon dioxide and 2 moles of water vapor
Where:
CH₄ (g): Hf = -74.6 kJ/mol
CO₂ (g): Hf = -393.5 kJ/mol
H₂O (g): Hf = -241.82 kJ/mol
Therefore, the combustion of 1 mole of methane releases;
-393.5 kJ/mol × 1 + 241.82 kJ/mol × 2 + 74.6 kJ/mol = -802.54 kJ/mol
Hence the combustion of 2 moles of methae will rellease;
2 × -802.54 kJ/mol or 1,605.08 kJ/mol.
An acid-base indicator is used to identify the presence of an acid or base. These indicators exhibit different colors depending on the solution that they are in. They are especially useful when completing titrations to determine the molarity of an unknown substance and is denoted as option D.
<h3>What is Titration?</h3>
This is done in the laboratory and involves the slow addition of one solution of a known concentration to a known volume of another solution of unknown concentration.
Acid-base indicators are used to determine the presence of an acid or base in a solution which is based on the colors seen when performing the chemical reaction.
It is used to calculate the the molarity of an unknown substance through the knowledge of the other parameters which is therefore the reason why option D was chosen as the most appropriate choice.
Read more Acid-base indicators here brainly.com/question/2815636
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Answer:
Correct answer is option (3) .
Explanation:
Hope it helpful....
